I have had both machines you mentioned (still have the E-Trac) and the V3i on my kitchen scale was around .5 pounds heavier (Yes, Kellyco's numbers are wrong). Some people have said the V3i is better balanced and others have said the E-Trac is better balanced. I like the E-Trac better but part of that (outside the weight) is that the V3i has that bigger box in the back and you have to slightly keep the unit farther from your body to swing it imo. Bigger to me is that each of us have certain sensitivities - be it a sensitive back or muscles or elbow, etc and for me the E-Trac was better but BOTH were poor overall. Each machine hits each of us differently.
All that said, I found both machines too heavy AND poorly balanced. I'm just about finished with my E-Trac mod (putting it on a straight shaft) and hopefully that fixes things. If your back, elbow, etc. are not sensitive to weight and repitition you might be ok though. I'm in very good shape but old injuries caught up with me a bit. I hope they re-do the E-Trac and balance it more like the CTX as even though it is heavy, the balance is spot on.
Good luck,
Albert